Freight cars are the equipment used to ship goods for a profit on the
railroad. The cars come in a wide variety of shapes and sizes to carry different
types of goods and materials.

At first there were just a few shapes of freight cars like the
box car, gondola and flat car. As the goods shipped on the railroad became more sophisticated,
so did the cars used to carry these goods. Forms of cars were invented for
conveying special materials like the tank car for liquids, the refrigerator car
for produce, etc. Specialized units were developed to freight things like
automobiles.

The basic material used to construct the freight cars
transitioned over time from wood to steel. Steel became more available, the
fabrication technology more sophisticated. and the material proved much more durable
than wood.

The
flat car is a uniform flat plane with wheels. Any type of goods might be
placed on top and strapped down for the ride. In general this might be
various types of equipment, lumber, steel or other materials that could
withstand being exposed to the weather.

At first the narrow gauge flat cars were built entirely of
wood. Eventually steel sided flat cars were introduced. Some wooden versions
were reinforced by adding a piece of old rail to the bottom
of the side sills.

Ore and
coal was a major cargo for the Rio Grande and it was most often carried in gondola cars. The
drop bottom style has a floor that hinges down to dump the load beneath the
car. Side dump gondolas have a visible hinge along the length of the side
and this allowed the side to drop open and the load to be dumped over the
side.